1. Field of the Invention
The present invention relates to a condenser. More particularly, the present invention relates to a shell and tube condenser for condensing vapor to liquid and having a subcooler for cooling the condensed liquid below the saturation temperature.
2. Description of the Related Art
In conventional condensers, such as condenser 10A shown in FIG. 1, condenser tubes 30A reduce the temperature of vapor entering the condenser, causing vapor to condense to liquid. Before the liquid leaves the condenser 10A, it is further cooled by subcooler tubes 50A positioned in a subcooler compartment 40A. The subcooler compartment 40A controls the flow of the liquid over the subcooler tubes 50A.
Preferably, no vapor enters the subcooler compartment 40A. Allowing vapor to enter the subcooler compartment 40A decreases the efficiency of the subcooler because the rate of convection heat transfer in the vapor phase is much less than in the liquid phase. Further, allowing vapor to enter the subcooler compartment 40A may allow vapor to leave the condenser 10A, thereby decreasing the efficiency of the system.
Engulfing the subcooler compartment 40A in a liquid reservoir 70A that extends along the full length of the condenser 10A will form a liquid seal that prevents vapor from entering the subcooler compartment. As illustrated in FIG. 1, the reservoir 70A must extend well above the entrance to the subcooler compartment 40A to prevent vapor from being entrained in the liquid flowing into the subcooler compartment. For example, the reservoir 70A must extend far enough above the entrance to prevent vapor within vortex 75A, which is typically formed at high flow rates, from entering the subcooler compartment.
The large reservoir of liquid required to form the seal can contribute significantly to the initial and operating costs of the condenser. For example, refrigerant has become very expensive due to industry changes that require it to be environmentally sound. Thus, the large reservoir of liquid refrigerant needed in a refrigerant condenser significantly increases its initial and operating costs.